Nuptiality patterns have undergone significant transformations in the past decades. The increase in cohabitation is one of the trends that has recently attracted growing attention in the demographic and sociological literature. However, research has focused almost entirely on the developed world. This study highlights that cohabitation is not a phenomenon exclusive to Western industrialized countries; in fact, its prevalence is higher in Latin America and the Caribbean, where the proportion of unions built on a consensual basis ranges from 12 per cent in Chile to 62 per cent in the Dominican Republic. Consensual unions in this region have some distinctive features: their historical roots, their pervasiveness among all age groups, and their status as a socially accepted context for childbearing. This study documents the current prevalence of consensual unions in Latin America, examines recent trends, and explores how these “unregistered” partnerships fit into the family formation process, i.e. their stability and their role in relation to childbearing. Using data from the Demographic and Health Surveys (DHS) for 9 countries, we examine how women in legal and consensual unions differ regarding their socioeconomic background and their family formation trajectories. A logit analysis is performed to gain further insight into the factors associated with being in an informal versus a formal marriage.